A sigmoidoscopy is an internal exam of the lower part of the large intestine (colon) using a short, thin, flexible lighted tube. The tube, called a flexible sigmoidoscope, has a tiny camera at the tip allowing the doctor to view the inside of the rectum and the lower third of the colon. A small biopsy instrument to remove tissue samples to be checked under a microscope for signs of disease can be performed during the examination.
A flexible sigmoidoscopy can help your doctor determine the cause of abdominal pain, rectal bleeding, changes in bowel habits, chronic diarrhea, and other intestinal problems. Your doctor may be able to diagnose the cause of diarrhea, bowel obstruction, diverticulosis, inflammatory bowel disease, anal fissures, and hemorrhoids, as well as find colon polyps that might be in this lower part of the colon.
Flexible sigmoidoscopy does not allow the doctor to see the entire colon. Therefore, any cancers or polyps farther into the colon cannot be detected with flexible sigmoidoscopy. A colonoscopy allows the doctor to examine the entire colon.
Flexible Sigmoidoscopy is generally performed at a hospital or outpatient center. During the test the patient is positioned on the left side with knees drawn up toward the chest. First, the doctor will do a digital rectal exam by gently inserting a gloved and lubricated finger into the rectum to check for any abnormalities.
Next, the sigmoidoscope is inserted into the rectum, and the patient will feel some pressure. Air is introduced through the scope to expand the colon and help the doctor see adequately. As the scope is slowly removed, the lining of the bowel is carefully examined. A hollow channel in the center of the scope allows for the passage of an instrument called a forceps for obtaining a biopsy if needed.
This procedure takes about 15 minutes. After the exam, patients may have mild abdominal discomfort. Patients may feel bloated or pass gas for a few hours as they clear the air from the colon. Patients will be able to return to a normal diet and routine after the procedure.
